1. Field of the Invention
The present invention generally relates to a cutting machine for cutting papers into pieces such as documents to be discarded or disposed and, more particularly, to a shredding machine or shredder.
2. Description of the Prior Art
A shredder provided with a paper feed mechanism for feeding papers to be cut into pieces is well known and disclosed in, for example, the German Pat. No. 2,214,799 first published Sept. 27, 1973.
According to the German patent, the paper feed mechanism provided in the shredder comprises a paper tray supported by a machine side wall for movement up and down between lowered and elevated positions, a spring means for urging the paper tray to the elevated position at all times, and a motor-driven paper feed roller positioned immediately above the paper tray in the elevated position. This paper feed mechanism is so designed that, assuming that a batch of papers to be shredded is placed on the paper tray and urged up against the paper feed roller through the paper tray by the action of the spring means with the uppermost paper held in contact with the paper feed roller, one or a number of the papers can be fed towards a rotary cutter assembly comprised of a pair of juxtaposed cutting rollers for shredding.
Since, according to the German patent, the paper tray is normally urged towards the paper feed roller, the placement of a batch of papers to be shredded on the paper tray requires an operator of the shredder to push the paper tray down towards the lowered position, causing the machine to require a complicated handing procedure.
Also, when the cutting rollers being driven in one direction during the shredding operation are reversed so as to rotate in the opposite direction for the purpose of interrupting the shredding operation and recovering the papers ready to reach the cutting rollers, the papers are fed backwards in a direction away from the rotary cutter assembly. However, according to the German patent, the path along which the papers are fed from the paper feed roller towards the cutter assembly is very limited and, therefore, no substantial space for accommodating the papers being reversed is available. This may bring about a problem of a paper jam, i.e., the possibility of the reverse-fed papers jamming somewhere in the path of travel thereof between the paper feed roller and the cutter assembly. In addition, when the paper jam is removed or when any trouble occurring somewhere in the machine is removed, the machine immediately assumes a shredding operation, and this may pose a hazardous condition to the operator.
Furthermore, in the machine according to the German patent, in the event that the paper or papers placed on the paper tray are not properly fed from the paper tray towards the cutter assembly by reason of a malfunctioning of the paper feed roller, the machine is usable to detect the occurrence of such malfunctioning. Therefore, the prior art machine according to the German patent has inherent limitations as to the workability and the handling convenience.